The invention relates to a method for avoiding an offset of a membrane of an electrodynamic acoustic transducer having two voice coils. Moreover, the invention relates to an electronic offset compensation circuit, which is designed to be connected to a coil arrangement of an electrodynamic acoustic transducer. The electrodynamic acoustic transducer comprises a membrane, a coil arrangement attached to the membrane and a magnet system being designed to generate a magnetic field transverse to a longitudinal direction of a wound wire of the coil arrangement. The coil arrangement of said transducer comprises two voice coils. Finally, the invention relates to a transducer system, comprising an electrodynamic acoustic transducer and an electronic offset compensation circuit of the kind above, wherein the electronic offset compensation circuit is electrically connected to the coil arrangement.
A method, an electronic circuit and a transducer system of the kind above generally is known in prior art. In this context, US 2014/321690 A1 discloses an audio system that comprises an electro-acoustic transducer connected to a first driver circuit and a second driver circuit. The electro-acoustic transducer comprises a first coil stacked on a second coil mechanically linked to a membrane, with the coils oscillating in the magnetic field of a permanent magnet focused by a pole plate. The first coil and the second coil are mechanically arranged symmetrical to the pole plate in a rest position.
While in US 2014/321690 A1 the first and the second coil are considered to rest in a magnetic zero position, reality shows that this condition cannot be fulfilled under all circumstances. Generally, such a deviation may be caused by a specific design and/or tolerances during manufacturing. As a consequence, the audio output of the transducer can be distorted, particularly at high power levels, and/or algorithms for calculating a membrane position can output wrong values.